#[non_exhaustive]
pub enum ThrottleReason {
    ConcurrentQueryLimitExceeded,
    Unknown(UnknownVariantValue),
}
Expand description

When writing a match expression against ThrottleReason, it is important to ensure your code is forward-compatible. That is, if a match arm handles a case for a feature that is supported by the service but has not been represented as an enum variant in a current version of SDK, your code should continue to work when you upgrade SDK to a future version in which the enum does include a variant for that feature.

Here is an example of how you can make a match expression forward-compatible:

# let throttlereason = unimplemented!();
match throttlereason {
    ThrottleReason::ConcurrentQueryLimitExceeded => { /* ... */ },
    other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
    _ => { /* ... */ },
}

The above code demonstrates that when throttlereason represents NewFeature, the execution path will lead to the second last match arm, even though the enum does not contain a variant ThrottleReason::NewFeature in the current version of SDK. The reason is that the variable other, created by the @ operator, is bound to ThrottleReason::Unknown(UnknownVariantValue("NewFeature".to_owned())) and calling as_str on it yields "NewFeature". This match expression is forward-compatible when executed with a newer version of SDK where the variant ThrottleReason::NewFeature is defined. Specifically, when throttlereason represents NewFeature, the execution path will hit the second last match arm as before by virtue of calling as_str on ThrottleReason::NewFeature also yielding "NewFeature".

Explicitly matching on the Unknown variant should be avoided for two reasons:

  • The inner data UnknownVariantValue is opaque, and no further information can be extracted.
  • It might inadvertently shadow other intended match arms.

The reason for the query throttling, for example, when it exceeds the concurrent query limit.

Variants (Non-exhaustive)§

This enum is marked as non-exhaustive
Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.
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ConcurrentQueryLimitExceeded

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Unknown(UnknownVariantValue)

Unknown contains new variants that have been added since this code was generated.

Implementations§

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impl ThrottleReason

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pub fn as_str(&self) -> &str

Returns the &str value of the enum member.

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pub const fn values() -> &'static [&'static str]

Returns all the &str values of the enum members.

Trait Implementations§

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impl AsRef<str> for ThrottleReason

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fn as_ref(&self) -> &str

Converts this type into a shared reference of the (usually inferred) input type.
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impl Clone for ThrottleReason

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fn clone(&self) -> ThrottleReason

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for ThrottleReason

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
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impl From<&str> for ThrottleReason

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fn from(s: &str) -> Self

Converts to this type from the input type.
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impl FromStr for ThrottleReason

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type Err = Infallible

The associated error which can be returned from parsing.
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fn from_str(s: &str) -> Result<Self, Self::Err>

Parses a string s to return a value of this type. Read more
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impl Hash for ThrottleReason

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fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher. Read more
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fn hash_slice<H>(data: &[Self], state: &mut H)where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
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impl Ord for ThrottleReason

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fn cmp(&self, other: &ThrottleReason) -> Ordering

This method returns an Ordering between self and other. Read more
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fn max(self, other: Self) -> Selfwhere Self: Sized,

Compares and returns the maximum of two values. Read more
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fn min(self, other: Self) -> Selfwhere Self: Sized,

Compares and returns the minimum of two values. Read more
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fn clamp(self, min: Self, max: Self) -> Selfwhere Self: Sized + PartialOrd<Self>,

Restrict a value to a certain interval. Read more
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impl PartialEq<ThrottleReason> for ThrottleReason

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fn eq(&self, other: &ThrottleReason) -> bool

This method tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl PartialOrd<ThrottleReason> for ThrottleReason

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fn partial_cmp(&self, other: &ThrottleReason) -> Option<Ordering>

This method returns an ordering between self and other values if one exists. Read more
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fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator. Read more
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fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more
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fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator. Read more
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fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
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impl Eq for ThrottleReason

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impl StructuralEq for ThrottleReason

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impl StructuralPartialEq for ThrottleReason

Auto Trait Implementations§

Blanket Implementations§

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impl<T> Any for Twhere T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for Twhere T: ?Sized,

const: unstable · source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for Twhere T: ?Sized,

const: unstable · source§

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<Q, K> Equivalent<K> for Qwhere Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

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fn equivalent(&self, key: &K) -> bool

Compare self to key and return true if they are equal.
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impl<T> From<T> for T

const: unstable · source§

fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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impl<T, U> Into<U> for Twhere U: From<T>,

const: unstable · source§

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> Same<T> for T

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type Output = T

Should always be Self
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impl<T> ToOwned for Twhere T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for Twhere U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
const: unstable · source§

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for Twhere U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
const: unstable · source§

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<T> WithSubscriber for T

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fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>where S: Into<Dispatch>,

Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
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fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more